Science research organization Battelle has deployed what's believed to be the first quantum-key encrypted network for full production use in the United States by encrypting all traffic between its Columbus and Dublin, Ohio, area facilities using the photon-based technique.

This is being done through the quantum-key encryption hardware from ID Quantique to protect data moving through a fiber-optics line in point-to-point fashion at about 1Gbps between the two locations separated by about 55 kilometers. Battelle senior research leader Don Hayford says photon-based quantum-key crypto holds fundamental advantages over traditional software-based crypto such as RSA and public key in keeping intruders at bay. But one reason quantum-key crypto hasn't come into widespread use is that there are also limitations, such as distance, which Battelle is tackling in its own research project.

Hayford notes that quantum-key distribution has special properties due to technical intricacies such as "spin or polarization" that can reveal whether anyone is trying to intercept or eavesdrop on encrypted data. "You know someone's tapping into the line," he says.

In addition, quantum-key distribution (QKD), as it's called, enables a crypto system that is much harder to break than methods that are susceptible to brute force attacks. There are so many ways to compromise software-based encryption methods today, says Hayford, that he doubts what's in widespread use today will survive five years.

But in spite of some perceived advantages, quantum-key crypto also has known drawbacks that have contributed to it not gaining more widespread use, though Swiss-based ID Quantique has seen some deployments in Europe and Japan, says Hayford. He adds there are also a few other quantum-key distribution vendors around the world, including Quintessence Labs in Australia.

One limitation to quantum-key crypto is related to the distance photon-based quantum-key can be expected to work, and that's reckoned to be about a 60 miles (100 kilometer) in distance today. The addition of equipment called quantum repeaters can boost that, but this type of gear is still largely under development, says Hayford.

The other challenge is that quantum crypto basically works under a point-to-point system at present. That's fine for some situations. After an extensive test period, Battelle has been running the ID Quantique gear in production for about a month now in that fashion using the Advanced Encryption Standard (AES) to protect its data, including Battelle's intellectual property and customer information, flowing between its two Ohio facilities. The ID Quantique cost is likely higher than a more traditional point-to-point set of encryptors, he acknowledges.

But developing this further to have quantum-key crypto support a more distributed system would aid in its adoption in commercial enterprises, such as banking and healthcare, and Hayford says Battelle is taking up that challenge. Battelle's intention is to develop a type of key-distribution node to support this and Battelle expects to have something along these lines in the 2015 timeframe. The goal is to be able to commercialize this research work to make quantum-key crypto appealing for enterprise use in a more distributed type of network.